macOS Persistent RAMDisk Works on macOS Big Sur. Reference Persistence There is a non-deprecated way to do it: Open the Script Editor app. Paste do shell script "~/.login" on quit do shell script "~/.logout" continue quit end quit File > Save , Select Application and Stay open after run handler and Save System Preferences > Users & Groups > Login Items tab > + button Add the application and mark it as Hidden To hide it from the Dock: Right-click the application and select Show package contents Open Info.plist and add NSUIElement 1 Create RAMDisk scripts $ touch ~/.login $ touch ~/.logout $ chmod +x ~/.login $ chmod +x ~/.logout Open ~/.login and paste, this creates a 1GB RAMDisk #!/usr/bin/env bash diskutil erasevolume HFS+ "RAMDisk" `hdiutil attach -nomount ram://2097152` && rsync -rauL --ignore-errors ~/.RAMDisk/ /Volumes/RAMDisk Open ~/.logout and paste #!/usr/bin/env bash rsync -rauL --delete --ignore-errors /Volumes/RAMDisk/ ~/.RAMDisk Mount the RAMDisk  $ ~/.login The RAMDisk should appear in Finder . Example use: PHPStorm caches on RAMDisk Create a folder called PHPStorm on the RAMDisk. Start PHPStorm > Help > Edit custom properties... and paste idea.system.path=/Volumes/RAMDisk/PHPStorm